The present invention describes systems and methods for treating disorders and/or conditions associated with the dermal level of the skin. Such disorders include acne, hyperhidrosis, bromhidrosis, chromhidrosis, rosacea, hair loss, dermal infection, and/or actinic keratosis. Methods generally involve administering nanoemulsions (e.g., nanoparticle compositions) comprising at least one therapeutic agent, such as botulinum toxin. In some embodiments, nanoemulsions are prepared, e.g., by high pressure microfluidization, and comprise a particle size distribution exclusively between 10 nm and 300 nm.